1. Field of the Invention
This invention relates to an apparatus for making a yarn, comprising at least one ring spinning mechanism and a drawing mechanism, which precedes the ring spinning mechanism and defines at least one draft path for drawing a fibrous roving and includes two delivery rollers defining a clamping nip for the drawn roving, wherein one of said delivery rollers constitutes behind the clamping nip a guiding surface for deflecting the drawn roving.
2. Description of the Prior Art
The strength of the yarn which is made by known ring spinning mechanisms will essentially depend on the twist which is imparted to the drawn roving by the traveler of the ring spinning mechanism. But as the speed of the traveler of a ring spinning mechanism cannot be increased as desired, there is a restriction regarding the twist which can be imparted to the yarn, particularly if the yarn is withdrawn at high speed.
In an attempt to provide a suitably compacted roving so that the guidance of the fibers of the drawn roving will be improved, it has been proposed (DE-A-1,178,749) to provide one of the delivery rollers of the drawing frame with grooves having the shape of an arrowhead or arc and to provide adjacent to said grooves a suction zone so that the fibers are moved toward each other by means of the grooves of the delivery roller and with the assistance of the stream of sucked air in the suction zone and the width of the roving strip is thus reduced. But the fibers cannot be moved toward each other as described unless the fibers move in the feeding direction relative to the grooved delivery roller. The required transverse force can be exerted only on those fibers which with their leading ends have already reached the grooved delivery roller of the drawing frame and which have not yet been gripped in the clamping nip between the delivery rollers. For this reason the roving as a whole is compacted only to a comparatively low degree particularly because the width of the roving will be increased by the clamping nip between the delivery rollers, which define the high-draft field of the drawing frame.